Pore Pressure Controls on Slope Failure and Transport of Sand into Deep Sea

You, Yao; Mohrig, David; and Flemings, Peter
[email protected]

Slope failure generated turbidity current is an important pathway for delivering sand into the deep sea. Accurate interpretation of deep water turbidite requires a complete understanding how sand is released from slope failure. Here we present a type of slope failure in clean sand deposit that can generate sustained turbidity current with periodic surges in the lab. In this type of slope failure, abrupt slope failure results in pore pressure drops and stabilization of the deposit where only grains on the surface could fall. Pore pressure dissipation then occurs until the strength of the deposit is reduced to generate a new abrupt failure event, which causes the pore pressure to drop and stabilizes the deposit, and resumes the grain-to-grain failure. This process repeats itself periodically and generates sustained turbidity currents with periodic surges. We find this type of slope failure could occur in longshore drift deposits and sandy deltas.

AAPG Search and Discovery Article #90162©2013 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Monterey, California, April 19-25, 2013